What is the meaning of the slope of the line in this context?

Answer:
The correct answer is D) The rate in which he burns calories
Step-by-step explanation:
We can tell this because the slope is always the change in y value over the change in x value. Since the y value is calories and the x value is minutes, we get the following.
Calories/minute
Which can also be written as calories per minute, which is a rate.